Specifications
Table Of Contents
- Contents
- Tables
- Figures
- 1 Introduction
- 2 Interface Characteristics
- 2.1 Application Interface
- 2.2 RF Antenna Interface
- 2.3 Sample Application
- 3 Operating Characteristics
- 3.1 Operating Modes
- 3.2 Power Up/Power Down Scenarios
- 3.3 Power Saving
- 3.4 Power Supply
- 3.5 Operating Temperatures
- 3.6 Electrostatic Discharge
- 3.7 Blocking against RF on Interface Lines
- 3.8 Reliability Characteristics
- 4 Mechanical Dimensions, Mounting and Packaging
- 5 Regulatory and Type Approval Information
- 6 Document Information
- 7 Appendix
Cinterion
®
ELS81-US Hardware Interface Description
2.1 Application Interface
53
els81-us_hid_v01.004 2017-09-27
Confidential / Preliminary
Page 27 of 107
The following figure shows the startup behavior of the asynchronous serial interface ASC0.
For pull-up and pull-down values see Table 10.
Figure 7: ASC0 startup behavior
Notes:
During startup the DTR0 signal is driven active low for 500µs. It is recommended to provide a
470
serial resistor for the DTR0 line to prevent shorts (high current flow).
No data must be sent over the ASC0 interface before the interface is active and ready to re-
ceive data (see Section 3.2.1).
An external pull down to ground on the DCD0 line during the startup phase activates a special
mode for ELS81-US. In this special mode the AT command interface is not available and the
module may therefore no longer behave as expected.
TXD0
RXD0
RTS0
CTS0
DTR0/GPIO1
DSR0/GPIO3
DCD0/GPIO2
RING0/GPIO24
ON
EMERG_RST
PU
PD
PD
PD
PD
PU
PD
PU
Power supply active
Start up
Firmware
initialization
Command interface
initialization
Interface
active
Reset
state
V180
VCORE
PD
PU
PU
PU
PD
PD
PD